On Sun, May 22, 2011 at 2:36 PM, Avi Kivity<address@hidden> wrote:
> On 05/22/2011 12:32 PM, Blue Swirl wrote:
>>
>> >> > +void memory_region_add_coalescing(MemoryRegion *mr,
>> >> > + target_phys_addr_t offset,
>> >> > + target_phys_addr_t size);
>> >> > +/* Disable MMIO coalescing for the region. */
>> >> > +void memory_region_clear_coalescing(MemoryRegion *mr);
>> >>
>> >> Perhaps the interface could be more generic, like
>> >> +void memory_region_set_property(MemoryRegion *mr, unsigned flags);
>> >> +void memory_region_clear_property(MemoryRegion *mr, unsigned flags);
>> >>
>> >
>> > Coalescing is a complex property, not just a boolean attribute. We
>> > probably
>> > will have a number of boolean attributes later, though.
>>
>> But what is the difference between adding coalescing to an area and
>> setting the bit property 'coalescing' to an area? At least what you
>> propose now is not so complex that it couldn't be handled as a single
>> bit.
>
> Look at the API - add_coalescing() sets the coalescing property on a
> subrange of the memory region, not the entire region.
Right, but doesn't the same apply to any other properties, they may
apply to a full range or just a subrange?
> It's a tree of regions, each level adding an offset, clipping, and perhaps
> other attributes, with the leaves providing actual memory (mmio or RAM).
I thought that there are two classes of regions, like PCI device vs. a
single BAR.